Proceedings of the Cotteswold Naturalists' Field Club (Volume 6)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1877. Excerpt: ... On the Middle Lias of North Gloucestershire. The Spinatus Zone; by Frederick Smithe, M.A., LL.D., F.G.S. i CONTENTS. I. Introduction II. Synonyms III. Petrology IV. Paleontology V. Lists Of Fossils 1. General 1. Leading Fossils 2. Special (Molluscan) 2. Abundant Fossils (a) Cephalopoda 3. Register of Fauna (6) Gasteropoda (c) Conchifera (d) Brachiopoda VI. General Remarks. VII. Notes And References: o: I. INTRODUCTION. Churchdown is well-known as a hill of circumdenudation, and on that account presents the geologist with an example of the adjacent hill country. We possess in it, a typical relic of those layers of strata that once stretched across the vale country, in certain directions as far as the eye can reach. In confining my remarks to the Middle Lias, I would observe that what constitutes the special value of this hill for the liassic geologist, is not its massiveness, for it is only some 580 feet above sea level, but its unity and completeness geologically, so far as the Middle Lias is concerned. There has been no disturbance of the sequence; since as the area of deposit gently subsided, the sediments arranged themselves in a tranquil sea. All, but the youngest stages of the Lias, as the Jurensis Zone or Mitford Sands of some authors, are present; each zone or phase of life of the period being characteristically represented. We say all but the Jurensis Zone, et supra, because there is reason to believe that all the younger jurassic beds that capped the hill were planed off, through the same depressing cause, namely, a faulting of the strata that more or less affected the integrity of all the outliers of the vale, and Bredon Hill more particularly. The Spinatus Bed of Opfel, Wright, and other authorities forms the uppermost Zone of the Middle Lias; i..